Telephone switching system



May 27 1930. N. H. SAUNDERS 7 1,759,869

TELEPHONE SWITCHING SYSTEM Einal Filed July 30, 1927 2' Sheets-Sheet 1' w Exam/v45 A m mill/1 5 I y 1930- N. H. SAUNDERS 1,759,869

} TELEPHONE SWITCHING SYSTEM OriginalFiled July 30, 1927 2 She ets-Sheet 2 EXCHANGE A "Exam/v45 T ,such f sts jfoi iiexample rthe ohefcomprising; conductors 101 end; 102; 1: flhe; extension o f the c01'inectiorr; to the: exchange. over theexchange-T; {It may'vbe' assuniedthatthe onef'comprisi'ng conductors 103',-10,1and 105 a result ofrjthelaestablishment 10f f this connection; az' circuit iskclosedl for. line relay ",2 ioflthei ilual 0&1]: repeater :DCR which cir- ,cuit ihcludes the twoictrl mk 'conducfiOIs103' arid .1050 am liexte d sl by Eof contacts 22 I ground onjLtheQJholdingQ .fcoriductor 312i closes -1 ea :cir'cuitl ffo'rgr-thex ,llpper'j niding #of supervisory control relay over 1 the circuit; incl-udingjmonta'cts- 60; [and s; 69-. Re

'. stay 53 operatesrgover its iufppe it and 25 "to the upper and lower windings .;of re1ay2.: CLinerelay'. 2 operates closes .a'rcircuitfor release: relayi3g Re'lea'se relay 3:} OPQI'MJBS: and grounds the 1 release conduc- V Q'itorgl'04ctomarkthisftriinkbusy tothe other I -liI Ie :switcheshzwingaccesszttheretoiat Con-. 2325 tactsylg 'andf grouzids; the"Kh IdinQgconductor-1412i at; contacts-F16. ,The;;; 1ic1ng of *closes'a holdingigci rcliit: forit'sel' etgcontacts V Y67independento 'contactssjfiO ind;69:,Iand "connects battery potential :throu'gh 2i :pI'OteQ-- tivelresista-rlce to the automatic exchang,e,end of] the; jsinr'lplexcontrohcircuit -whichii clud'es Jine relay 51," trunk conductors @311 and in parallel; and supervisory relay 1302;, at the;

' 1413011 board- This 1. C CiIBCLIBi I ground 'pote'nti a1 connected: to the. fiaiitomaticexchange end"thereoflati contacts l2, vat Con- {tactsi37Q zinld alsdiizia the resistance and to the toll board eiid thereofa t gcontacts 30,7.

.;The' connectiorir or battery potential V to-the f t automatic exchange end' of;th s-xcircuit p110? d'uces a, current flow; :thereoverg and" causes the i energization ofv-line relay 51 at the exchange c jA d alsorelayj3o2the t0fl bqerdei. 3 2* i J .51 in energizing; closes' acirc ltf el ifiia 1,,-energiZing circuitfm: th i ppei' W-. c. v 1 relay 7 during themomentary'deenergization" :of the. l ne/relay 5 1,perforn1s theffollowing by 5 1 Relay 52'ioperetesvendgopensgthe n t g (of J relay; 53.. by aSeparati gGOIJt@Gfi 0',

V =P ieparesa' clr i itni r re im 1m L indiczttestqth tell-icperat orthatjzi c011 I 'erationicloses; the r circuit] of re1ajq30l by 0 QS I gzQ l Relay 1 tpp r ti g, ubs itu s b ttery pbte it i thrwghi a ar separ ting", contacts 307} endclosihg coritacts'; V 306;, tild -also" opens theLCircuit of lempiL? I this trunk line cel lseslslthei 1iheswvitchr LS to I operate ifithe usual manner andiselectfthe outf goinghranchof an idle 'tr'l l nklin'e extending to iay 55 operates and closes. the; circuit-10f relay f contacts 71 closes a circuit for. relays 56111 vser1es',"th1s ClI'Clllt' includlng contacts 68.

i6'8end'; Bela-$753 i's difierentiallyWound. i

in nd contacts-.65 discomiectsbattery potential from I thei'excharige: end' of the control ci rcu it far'id f :aigai'n 'sub'stitutesthe normal ground'c nn'ecitionsthereto. Since batteryi'potentialiis-riow Y ;.c0nnect,ed'to the toll board end of the control circuit Lendgr'ouncl" potentialis connected :to the exchange end thereof, relay 302land line gizirigggagein closes thecircuit 'offreley 52. Smce thecperations described respon sive to therel'e'ase of 51,: namely 'theoper'at i'onsavoi lt'ioho'f relay 53 take placeflin a comparatively Q} I sh ort" t1me,' rel ay '52 does not restore rd-iirihg, th s=1i1terval, anci'relay 302 at,.the toll board. 1'

'r'ated oiily ior'an interval;..- V

circuit changes z-By th'eclosure 0f: contacts it; I

and' 78 a bridge is placed'across theggconductor's 11 5 and l'l7i:(after-relry 53vis deic'i-i 1 ica uses the" energizetionof the line and they reIeaSeETeIeyS (hot-shown) in the selector S associated With the dual call repeater DOB 1 ,therebypreparing this: selector for opere1 ,tion. vAtcontactsBOa circuit is-'preparedgfor v during dialling asv ill-be described-prestor the fioiimgl groundi co ihection 7 i1 i i at theitoll board end of the control circuitiby' and: prepares'the circuit of lamp sep rating contacts 803 and cl'o's'ingcoiitzicts 304'. Since" hettery potentiaiis how connected to c v *bbthiids of the [control circuit, both rel'ziy v f branch;s elect'ed'gby the Imes itc'hjLS; is the I I of thetrunk comprisingconductors i311 and v I =3 l2=termina ting a tfithe toll boardatthezexchangeQTjiii J LCk JJZ 5* 302 'a'tfthe. e311 board and'iihe relay 5 l atvthe" e chmigeATeh-mse. Relayffil, in releasing-5. closes a'circuit for'relay 55 which includes cents-M1368 oi-relay 52(re1ay 52rbe ingislow i L :ectinguhairitains its-armature; attracted'zforg arr-interval after r its circuit is opened); j 'Re-i L 554 at contacts 73. Relay 54 operates. ahdfat an dnlso contacts-'33. Relay"? operates and I -locksr-itselfto the'jholding conductor 1% et I i i ,icorit'ect's 34i,cl0ses the circuit for'the polariz'g 111g, w rling ofrele'y 6 st contacts 31'and'by seperatlng contacts 33 opens its initialenery giz' ing' circuit andby closing contacts 32c1oses v' Q a. c1rc1 11t. for the lower Wmdingfofrelay; 53 theflatter circuit likewise including contacts 7? i end thereforesthe energization of its lower winding causes this relay to. release; f Reliiy 1 053', reieasingmpens the locking circuit 7 its upper Winding at contacts :67 "andopen's e j the circuit ofits" lower Winding at, contacts I 68, byseparatiiig contacts 66 and closing relaysi'55, 54, 7,afld 56, an clthei 'dee rergiza-f Relay 56 which is-energized in series With tuat'edf and relay 51 is reoperated')/Which short 'circuiting the lower Winding ofrelfxy P ently I At contacts 81- Z a condenser; bridge I ent potent-ialto saidconductor'at the manual switchboard to control'the'operation ofsaid -sw itch to connectwith said'called line; Y 3

24 In a telephone syste'mQatrunk line ex tending from anexchange to amanualswitclr board, a calling line at, said exchange and means for connecting it with-said trunk line,

' means responsive to the establishment of'said connection forcaus ng a current'flow over a conductor of said trunk line: in" one drection to signal the operatorat said manualswitchboard, a called line, an automatic switch asso- I ciated with said; trunk line,"1an automatic switch associated with saidtrunk line at the exchange, means responsive, to the operators answering the callfor reversing said. current flow over said conductor, and means cont'rolledby the operatorfor intermittently 1nterrupting the reversedfcurrent flow to cause said'switch to operate and connect with said called line.

, 25. In a telephone systenrgaltrunk line ex- A tending from an exchange to a manual switch!- board,a ,calling line at said" exchange and -means' for connecting it with said trunk line, means responsve to the establishmentof said connection for causinga'current flow over a conductorrof said trunk'line inone direction x to signal the operator at said manualswitchboard, a called line,'an automatic switch associated with said trunk line at "the exchange,

" means responsive to "the operatorsanswering the call for reversing said'current flow over said conductor, means controlled'by the 0p- 7 BIatOI' QfOI intermittently interrupting the reversed current HOW to cause said switch to operate and connectwith said called line, and a means responsive to the party on the called 7 line answeringthe call for changing the value o 26..- In a telephone system, a trunk line having two "branches, a 'switchiassoeiateid with a each branch, means responsiveto digits sent;

of the reversed currentlflow to notify the operator that the call is 'answered'.;

over said 'ljtrunk, line"- for operating said switches separately and means responsive to a I particular" digit for disassociatin'g :oneof the ,switcjhesfro'm itslnorm'ally'associated branch.

27, Inia telephonesystem,flines, atrunk having. two branches, ajswi'tch associated with each branch,means'foroperatmg'one of said switches to extend a connection to one of said lines and for operating the other of said switches to extend 7a connection to another' of said lines, and means responsive to the operation of the other of saidiswitc-hes toa particular extent for-disassociating'said other of said switches fromits normally associated branch, v

' o ,28. Ina telephone system, atrunk linecom prising two conductors, a calling; and called 7 line, automatic switches, means "controlled I over said two conductors in parallel :foreX- tending a connection'to'said calling line via certain of saidautomatic switches and means series.

eanng'and sa 'c i lint "29. i In 'aftelephone syst ating said switches separately, the. switch operateddepending on" whether or not a sue scriber has connected with said trunk line, 30. In atelephone'system, atrunk "liner:

haying three branches'at one end,'calling and calledflines, means forextendiiig a c'all'from the calling line Via one of said branches and the trunk line, and means controlled over, the,

trunkline for establishing a connection bee tween thecalling and called lines'vvia either the first and secondbranches in series or the second and third branches in series.

'31. Ina telephone-system, a two conductor trunk'line, branchesof the trunk line each-in;- I I eluding two conductors, automatic switches o terminating said branches, calling and called lines, andmeans controlled over the two con ductors ofthe trunk line in parallel and the two conductors of the associated branches' in series for directively operating the respec-'; 9

tive automatic switches to establisha connec- 51g tion between the calling and called linesQ" l 32. In a telephone system, a trunk line com 3 j prising 'two conductors, a'plurality of 1 1 a branches of said trunkline each comprising L two conductors, an'd'a line relay controlled I a over the twoiconductors of the trunk line in a V parallel-for repeating impulses successively Q? 3 over the two conductors ofeach-branch in 33Q- In a telephone system, a trunk conductors ofv the other branch in series.

plurality of branches of the trunk line,'and

a relay controlled over the trunk line forr z separately. repeating impulses overfsa i'd branches in pre-determined succession:

3 5. In a telephone system, a trunklin'e having a, plurality of branches, a line relay cone e 34,-. In atelephone system, a trunk line, a-

lia trolled over said trunk'line,and impulsing f contacts on;said relay included successively in'fsaidfbranches in predetermined'orden. j o.

l 36. In atelephone system, a branched trunk .i e

12; v series of impulses transmitted overthe trunk 7 line, a relay responsive to a plurality'of' line, means for causing said relayto repeat thefirst series of impulses over one branch of the-trunk line to'extend a conn'ectiontoai q r a called line, and means'r'esponsivetothecom [comprising two conductors, branches ,of'the Y trunk linelealch comprising two conductors, I and v a line relay controlled'over the two'con-f duc'tors of the trunk line in parallel for ini- Q 7 tially repeating impulses over the two con ductors, of one branch inseries and for subsequently repeating impulses overthe two 

